1. Field of the Invention
The present invention relates to a method and apparatus for detecting departure of a running automobile from a traffic lane, characterized by mounting, on an automobile, steering angle detecting means for detecting a steering angle based on the steering wheel operation of a driver, a television camera, and a computer for processing a video signal from the television camera, and comparing the steering angle detected by the steering angle detecting means with a virtual standard steering angle that is calculated by the computer to drive the automobile without lane departure.
2. Discussion of the Background
There have been proposed a number of methods for autonomously guiding a running automobile to a destination. One of the present inventors has proposed such a method in JP-B SHO 62-33607, for example. This prior art method comprises setting a suitable number of target points between a starting place and a destination, causing an automobile to follow the target points successively, thereby automatically guiding the automobile to the destination.
There has been proposed an extension of the prior method in a technical paper (1990 JAPAN-U.S.A. Sympo. on FA), one of the authors of which is one of the present inventors. In the extension a method is presented in which an automobile is autonomously guided along a traffic lane with a reference live like a lane marker.
In view of the above, it is one object of the present invention to provide a method and apparatus for detecting departure of a running automobile from a traffic lane by comparing a steering angle based on the steering wheel operation of a driver and a steering angle that is calculated to drive the automobile along the traffic lane.
The present invention discloses a method characterized in that it is detected whether an automobile is running in a direction departing from a traffic lane, has already departed from the lane, or is running in a direction recovering from the departure, by mounting on the automobile steering angle detecting means for detecting a steering angle based on the steering wheel operation of a driver, a television camera for taking pictures of the lane and a computer for processing the pictures taken by the television camera, using the television camera to take pictures of markers on the lane while the automobile is running on the lane, inputting video signals into the computer, using the computer to process the input signals, thereby setting a virtual reference line, forming a cubic curve approximating the set virtual reference line, calculating a virtual standard steering angle from a coefficient of a function representing the cubic curve, and comparing the steering angle detected by the detecting means based on the steering wheel operation of the driver with the virtual standard steering angle calculated by the computer; and also discloses an apparatus for carrying out the method.
Since anything present on a lane, including a lane partitioning line, curbstones, the shoulders of a road, etc., can be used as the lane markers referred to above, in the present invention, it is possible to detect the departure of an automobile from any traffic lane, thereby making it possible to greatly reduce the number of traffic accidents and the like.